Doronicum micranthum Z. F. Bai & Xue L. Chen, 2025

Bai, Zengfu, Zhang, Guiyuan, Zhang, Zhihua, Li, Anzhong, Li, Hao, Wang, Geyang, Chen, Xuelin & Zhang, Ji, 2025, Doronicum micranthum (Asteraceae, Senecioneae): a distinct new species from western Qinling, China, PhytoKeys 267, pp. 37-42 : 37-42

Doronicum micranthum Z. F. Bai & Xue L. Chen sp. nov.

Figs 1 , 2

Type materials.

China • Gansu: Hui County, Yuguan town , in broad-leaved forests, alt. 2000 m, 10 May 2025, Zengfu Bai BZF 20250510005 ( holotype NWTC!; isotypes NWTC!) .

Paratypes. China • Gansu: Hui County, 10 May 2025, Z. F. Bai & Xue L. Chen 20250510006, 20250510007 ( NWTC) ; 21 June 2025, Zhi Zheng 637 ( NWTC) .

Description.

Perennial herb. Rhizome fleshy, swollen, with numerous fibrous roots. Stems solitary, erect, 35–60 cm tall, unbranched or bearing only floral branches, green, sparsely glandular-puberulent. Basal leaves long-petiolate; leaf blades obovate-oblong, 1.2–7 cm long, 1–6.5 cm wide, apex rounded, base subcordate; petioles slender, 3.5–7.5 cm long, narrowly winged. Mid-cauline leaves ovate-oblong, sessile, 5.5–10.5 cm long, 3.5–7 cm wide, apex obtuse or mucronate, base cordate, semiamplexicaul, margin remotely dentate proximally, subentire distally, both surfaces subglabrous; upper cauline leaves ovate or ovate-lanceolate, 2–8 cm long, 1.5–6 cm wide, apex shortly acuminate, base cordate, semiamplexicaul. Capitula (including ray florets) 0.5–1.4 cm in diam., usually solitary; peduncles 2–13.5 cm long, glandular-pubescent. Involucres hemispheric, 4–8 mm long, 0.5–1.2 cm in diam.; phyllaries in 2–3 series, outer ones lanceolate, 1.5–2 mm wide, margin ciliate, abaxially glandular-pubescent on lower half, distally glabrous or subglabrous; inner ones narrowly lanceolate, ca. 1 mm wide, margin ciliate, abaxially glandular-pubescent; apex of all phyllaries long-acuminate, equal with or slightly longer than disk florets. Ray florets 18–25, yellow, 5–8 mm long; tube 1–2 mm long, glabrous; lamina oblong or oblong-elliptic, slightly spreading, 4–6 mm long, ca. 2 mm wide, 4 - veined, apex 2–3 - denticulate. Disk florets numerous; corolla yellowish green, 3–4 mm long; tube ca. 1 mm long; limb campanulate-funnelform, lobes ovate-triangular; anthers usually not exserted, ca. 1.5 mm long, base obtuse; style branches bifid, apex obtuse or truncate. Achenes brown, 10 - ribbed. Pappus absent in all florets.

Phenology.

Flowering from May to June; fruiting from July to August.

Etymology.

The specific epithet refers to the smallest capitula among all known species in Doronicum in China. Hence, the Chinese name “ 小花多榔菊 (xiǎo huā duō láng jú) ” is suggested.

Distribution and habitat.

Doronicum micranthum is hitherto known from Hui County ( 33°39'39.23"N, 106°19'45.32"E; 33°40'45.20"N, 106°21'56.13"E), Liangdang County ( 33°41'27"N, 106°19'35"E) of southeastern Gansu (Fig. 3 ). It grows in broad-leaved forests at elevations of 2000–2260 m.

Notes.

Doronicum micranthum is unambiguously distinguished from D. conaense , D. stenoglossum , and D. calotum by its characteristically small capitula (consistently less than 1.5 cm in diameter) and the complete absence of a pappus in all florets. Furthermore, D. micranthum possesses a prominently enlarged rhizome, a diagnostic feature not shared by the other three species discussed here.

In contrast, D. conaense , D. stenoglossum , and D. calotum all possess larger capitula (exceeding 1.5 cm in diameter) and a pappus, though its distribution varies: a pappus is present in all florets of both D. stenoglossum and D. calotum , whereas in D. conaense , the ray florets are epappose and the disk florets are pappose.

Figures

Figure 1. Habitat and habit of Doronicum micranthum.

Figure 2. Detailed morphology of Doronicum micranthum. A. Habit; B. Rhizome; C. Leaves; D. Top view of capitula; E. Bottom view of capitula; F. Ray florets; G. Disk florets; H. Phyllaries; I. Infructescence.

Figure 3. Distribution of Doronicum micranthum.